Samsung Electronics’ ssnlf mobile recovery was under pressure on Thursday after it delayed shipments of its premium Galaxy Note 7 smartphone amid reports of exploding batteries, wiping almost $7 billion off its market value.

Investors drove the stock to two-week lows after the global smartphone leader told Reuters late on Wednesday the shipments had been delayed for quality control testing, and that shipments to South Korea’s top three mobile carriers had been halted.

Faults with the new flagship device could deal a major blow to the South Korean giant, which was counting on the Galaxy Note 7 to maintain its strong mobile earnings momentum against Apple Inc’s new iPhones expected to be unveiled next week.

“This is some major buzz-kill for Samsung, especially given all of the hard-earned excitement that products like the Note 7 have been garnering lately,” IDC analyst Bryan Ma said.

“Be careful out there, everyone rocking the new Note 7, might catch fire y’all,” one user said in a YouTube clip showing a burnt Note phone. It was not immediately possible to confirm the veracity of the clip.

Samsung’s shares, which hit a record high of 1.694 million won last week, dropped 2.5% as of 05:08 GMT, and Samsung SDI tumbled 6.1%, versus a 0.2% fall for the broader market.

DAMAGE CONTROL

Last year, production problems for the curved displays for the Galaxy S6 edge model resulted in disappointing sales, and Samsung risks a repeat this year if it cannot address the Galaxy Note 7 problems quickly.

Its mobile profit is on track to post annual growth for the first time in three years, thanks to robust sales of the Galaxy S7 and S7 edge devices that it launched in March to critical acclaim.

The Galaxy Note 7 received similar praise, raising expectations for strong sales in the second half. Samsung said in August demand for the new handset, priced at 988,900 won ($882) in South Korea, was far exceeding supply, pushing the firm to delay the launch in some markets.